Subtract 6/20 from 70/21, Solve 3 7/21

Subtract 6/20 from 70/21

1^st number: 3 7/21, 2^nd number: 6/20

70/21 - 6/20 is 91/30.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 20 is 420

Next, find the equivalent fraction of both fractional numbers with denominator 420
For the 1st fraction, since 21 × 20 = 420,
70/21 = 70 × 20/21 × 20 = 1400/420
Likewise, for the 2nd fraction, since 20 × 21 = 420,
6/20 = 6 × 21/20 × 21 = 126/420
Subtract the two like fractions:
1400/420 - 126/420 = 1400 - 126/420 = 1274/420
After reducing the fraction, the answer is 91/30
In mixed form: 31/30

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